Researchers receive DOD grant for implantable muscle stimulator

IMAGE: A rendering of the flexSTIM implantable muscle simulator.
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Credit: Case Western Reserve University School of Medicine

A team of researchers led by Kath Bogie, DPhil (PhD), a biomedical engineer and associate professor of orthopaedics and biomedical engineering at Case Western Reserve University School of Medicine, and colleagues from Case Western Reserve and other institutions, has received a $1.8M, three-year grant from the U.S. Department of Defense to develop an implantable muscle stimulator for preventing pressure ulcers and deep tissue injuries to the buttocks. These serious medical conditions, which are caused by lying or sitting in one place for long periods of time, can lead to severe pain and infection, even death.

Bogie's co-principal investigators are Christian Zorman, PhD of Case Western Reserve University School of Engineering, Douglas Shire, PhD of the Cleveland VA Medical Center, and David Keicher and Marcelino Essien of Integrated Deposition Solutions Inc., Albuquerque. They will collectively develop and test flexSTIM, a small, flexible, fully implantable stimulator with electrodes that, at the touch of a button, will provide intermittent stimulation to the three gluteal muscles that comprise the buttocks. By mimicking regular weight-shifting -- consequently increasing muscle bulk -- the stimulation will improve muscle health and help prevent pressure ulcers and deep tissue injuries.

"We are grateful to the Department of Defense's Congressionally Directed Medical Research Programs for providing this funding," said Bogie. "FlexSTIM will eventually be suitable for virtually all patients with spinal cord injury and others with debilitating medical conditions."

In cases of spinal cord injury, motor impairment causes muscle atrophy that changes both muscle quantity and quality, increasing the risk of pressure ulcers and deep tissue injuries. Patients are often unable to sustain regular employment or take part in community life, resulting in emotional distress. Caring for them can be costly and time intensive. The only way to heal is to stay off the injured area, which can lead to weeks or even months of bed rest, significantly reducing quality of life.

Previously, Bogie and her lab team implanted a system that provided intermittent stimulation in five people with spinal cord injuries. Not only did they not develop pressure ulcers and deep tissue injuries, they regained healthy tissue under the skin and increased gluteal muscle mass. However, the original system included wires that protruded from the skin and connected to an external control box, leaving small holes that were difficult to keep covered and clean and which were susceptible to infection.

"Following the positive results we achieved with that system, our team was contacted many times over the years by people asking for a device that could be fully implanted," said Bogie. "Other prevention methods they tried failed and they were desperate for a new alternative."

The benefits of the new fully implanted system will include increased quality of life and decreased cost of medical care. Risks will be minimized because only a small incision will be needed to implant the 4mm-thick device. Current commercially available stimulators require major surgery and must be located in body regions with ample soft-tissue cushioning, such as the abdomen. Implanting flexSTIM will be an outpatient procedure and only require local anesthesia.

Bogie projects that clinical trials of the device in humans could begin within five years, with translation to the market within ten years.

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For more information about Case Western Reserve University School of Medicine, please visit: case.edu/medicine.

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